From how to describe what happens to you at school, it's not okay. It is an expression of huge disrespect to call attention to your mistakes loudly, informing others about it who have nothing to do with it.
If the teacher(s) also reacts exaggerated about something you got wrong, it does have an effect on your classmates. They see an adult overreacting at you in front of them as if an unspoken social rule tells: it's okay treat this young man with disrespect. It's not so unsurprising they feel free to try being disrespectful to you too. Awful stuff if they get away with it as they seem to way too often.
I really like SilentScream's idea, because that's something for you to do. They can talk loudly/shout across the room? You can do it too.
Show them that you don't get worked up stupid mistakes. They disrespect you so openly, because think they can get away with it and that you won't make fun of them in return. Observe what happens if you do make fun of them in return, I bet that if you'll listen closely, you'll hear some awed whispers about how funny what you said was and how stupid it made that student look that tried to make you look stupid first. Maybe someone will actually later compliment you about how smart and fun you handled that.
If it ever gets worse than that or you just don't feel like putting up with it anymore but don't know what to do: 17 and "almost an adult" or not, you should then really talk about this with a counsellor or a teacher you trust and inform your parents.
Even if an autistic person weren't too badly troubled by such rudeness and bullying, it must be stopped. Being disrespectful to someone is not okay because other classmates, teachers and other students of your school that have nothing to do with it can still see it. They might get the idea that they too can treat you like that, because nobody will step in to stop it.
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Autism + ADHD
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The trouble with having an open mind, of course, is that people will insist on coming along and trying to put things in it. Terry Pratchett